Circulating system for steam generators



s. F. CRABB CIRCULATING SYSTEM FOR STEAM GENERATORS Filed Jan. 21, 1921 Z5. 1'- y mm Patented Sept. 4, 1928.

UNITED STATES PATENT OFFICE.

SlIlA-S F. CRABB, F PITTSBURGH, PENNSYLVANIA, ASIGNOR TO JAMES M. SELDEN,

OF PITTSBURGH,

PENNSYLVANIA.

GIRCULATING SYSTEM FOR STEAM GENERATORS.

Application filed January 21, 1921. Serial No. 439,019.

My invention relates to steam generators and more particularly to generators having aforced water circulation.

One of the principal Objects of my invention is to provide a steam generator in which the circulation of water is increased mechanically as compared with the circulation obtained in generators of the usual type, wherein the circulation is effected solely by the thermic expansion of the water contalned therein. Another object is to provide means to regulate automatically the circulatlon of the water in proportion to the amount of steam produced by the generator. A furl5 ther object is to provide a steam generator in which the formation of scale and other deposits within the tubes thereof is reduced to a minimum, if not entirely eliminated. Further objects and advantages of my 111- vention will appear from the drawings and specification forming a part of this application.

In the drawings: i Fig. 1 is a sectional cross-elevation of a steam generatorbuilt in accordance wlth my invention.

Fig. 2 is a top plan view taken along the line 22 in Fig. 1.

Fig. 3 is across-sectional elevation, taken 0 along line 3-3 in Fig. 1, showing the pre ferred type of circulating pump used in my invention.

Referring especially to Figure 1, my device consists of the heating member 1 com- 5 posed of any desired'number of separate coils suitably nested together to absorb the heat produced by the burner 2. As shown in Figure l, I have represented the heating member made up of .6 separate coils, wound i in parallel and in such away as to make all coils of substantially the same length. The inlet tube 3 of each coil is located at the top thereof and is connected directly with the discharge end 4 of a feed pump 5 provided individually for each coil. These pumps are preferably of the rotary type as shown n Figure 3, for example, and are enclosed 1n a suitable housing 6 having a common suction intake 7 for all the pumps. .The discharge ends of the pumps are preferably provided individually for each coil, and for this purpose the pumps are separated from each other by the partition walls 8 cast integral with the housing or else secured thereto in any appropriate manner. Openings 9 are provided at the top of these partitions to allow the-even distribution of the incoming suction-water among the various pumps.

The pump 5 may be rotated by any suitable source of power. In Figure 1 I have shown the simplest and most logical method of driving these pumps which consists in the use of a rotary steam engine 10 provided with a shaft 11, extended to accommodate the various pumps secured thereon, and run ning in the bearings 12 and 13 supported by the end plates 14 and 15. In this drawing I have shown the casing of the steam engine formed integral with the pump casing.

The lower ends 16 of the heating coils are directed upwardly into a manifold 17 which communicates, by means of the pipe connection 18, with the steam inlet 19 of the steam engine. The steamis exhausted through the port 20 and is conducted by the pipe connection 21 into the top of the steam receivers tank 22, filled about half-way with water, and supported by the standards 24. It will be observed that all of the steam generated in the coils 1 passes through the auxiliary engine 10 and drives the pumps 5 at a speed which is in direct proportion to the amount of steam generated. Consequently, the Water is fed into heating coils in direct and automatic response to'the quantity of steam that is generated. I

The intake 7 of the circulation pumps is connectedto the receiver tank by the suction pipe 23, communicating With the bottom of the tank. In this suction pipe I provide a check valve 25, of any suitable design, to prevent the Water from, flowing back into the receiver.

In the drawings I have shown the generator provided with a pro-heating coil or economizer 26 located above the steam generator coil. The inlet tube 27 of this economizer is connected to the discharge end of any suitable boiler-feed pump, (not shown on the drawing) whereas the outlet end 28 of the economizer is directed into the lower end of the receiver tank. entering the latter at the port 29. Q'With this arrangement, it will be seen that all the water entering into the 16 coils with water, prior to ceiver will first be pre-heated by the combustion gases while passing through the economizer.

The steam generated in the coils is collected in the receiver tank 22 and is directed therefrom to the main engine, driving the vehicle, by means of suitable piping, connected to the elbow 44, provided on the tank. 'As will be understood,my invention may be operated with. any suitable source of heat; but I have shown in the drawings. the heating system which I prefer. It consists of the disc burnerQ, provided with any suitable number of flame-jets 30 and the central hub 31. A mixture of air and highly atomized hydrocarbon fuel is forced into the burner Qby means of a specially designed fanblower 32 joined to the burner by the pipe connections 33.

All parts exposed directly to the action of the flames are enclosed in a fire-box 34, adequately lined on all sides with insulating material, 35 and 36, to prevent the radia tion of heat, and provided with a cover 87, also insulated, which serves as a base for various external parts of my invention.

The gases of combustion, after having given up their heat to the steam generator and economizer, box into the atmosphere through the suitably shaped flue 38 provided adjacent to the top of the fire-box. The expulsion of these gases is" greatly assisted by the pressure existin forced circu ation created bythe fan-blower For the purpose of filling the heating putting the system into operation, I provide at. the end of the manifold tube 17 the pipe connections 39, extending through the cover and terminating with the valve 40 and the pipe nipple 41, to which a hose may be attached. Similarly, the economizer coil and receiving tank are filled through the opening I 42 provided at the top of the tank and norly sealed with the threaded plug 43.

Having thus described the various parts of my invention, the operation and advantageous features thereof will be easily understood from the following description:

Assuming that the system be properly filled with water and the fuel'ignited, all of the steam generated in the heating coils will rise into the manifold, enter the housing of the rotary steam engine and drive the latter as well as the circulating pumps mounted on its shaft extension. The steam then passes into the receiver tank through the pipe connection 21 and is finally de livered to the main power engine by the way of the elbow fitting 44.

The feed water is pumped into the economizer coil 26'where it is preheated before entering the receiver tank,

are expelled from the fire-' within the fire box due to the always be somewhat engine is running and ,fuel is supplied to the burner. The various arrows shown in the drawings indicate the normal direction of the flow of the water, steam and combustion gases.

One of the more important features of my device lies in the fact that owing to the mechanically forced circulation, the diameter or cross-section of the heating coils can be made much smaller and the coils can be much longer than would be possible in tubular boilers working with the natural circulation due to the temperature of the water alone. The available heating surface, for a given amount of water circulated, is therefore greatly increased thus allowing a very rapid generation of steam.

It follows also, from the increased speed of water circulation, that the deposits of scale, oil,v or other detrimental matters in the heating coils are greatly reduced, thus conserving the efficiency of the generator culation is forcibly checked and the water is compelled to travel downwardly in the heating coil and is thus exposed, in the lower tubes, nearest the flames, to the greatest temperature and is rapidly vaporized.

The steam pressure in the manifold will reater than in the receiver tank; the di erence being due to the small amount of energy required to operate the auxiliary rotary steam engine driving the circulating pumps. This difference is however sufiicient'to insure the right rotation of the circulating pumps and hence, the correct operation of the complete system.

It will also be noted that the system is self-adjusting because the greater the amount of steam consumed by the main engine, the greater also will be the difference in steam pressure between the heating coils and the receiver; therefore the auxiliary steam engine will run faster and increase the circulation of water in the heating coils.

Mention'is also made herewith of the fact that the heating coils, especially the lower ones, can never be burnt out on account of becoming dry as often occurs in boilers of the so called flash-type, as long as there with water.

As will be understood, there may be slight changes made inthe construction and arrangement of the details of my invention withoutdeparting from the field and scope ofthe same, and I intend to include all A such variations, as "fall within the sphere of the appended claims, in this application in which the preferred form only of my in vention has been disclosed.

What I claim is:

1.In a steam generator, the method of causing, positive circulation within the generator consisting in creating a difference 1n pressure between portions of. the generator and vcausing such differential pressure to operate mechanical water forcing means for supplying water from the portion of lower pressure'to the portion of higher pressure.

2. In a steam generator closed at all points except an inlet for water and an outlet for steam, the method of causing positive circulation within the, generator cons1sting in creating a difference in pressure between portions of the generator and causing such differential pressure to operate mechan-- ical water forcing means for supplying water from the portion of lower pressureto the portion of higher pressure.

3. The method of maintaining circulat on between ortidns of a closed steam generator, Whic consists in generating steam 1n one portion of the generator at higher pressure than in the other portion and causing the differential pressure between the .two portions to operate mechanical Water forcing means to supply water from the low pressure portion to the high pressure portion. r

4. In a. generator for generating steam, an

element of-large capacity relative to its exterior surface, an element of small capacity relative to its exterior surface, means for r heating the exterior surface of said element of small capacity, an outlet forrsteam leading from said element of'small capacity to said element of large capacity, actuating" means arranged in said steam outlet and operated-by the steampasslng therethrough, an inlet for water leading from-said element of largecapacity to said element of small capacity, and Water forcing means in said inlet adapted to force water therethrough, said water forcing means being arranged to be operated by the actuating means in said. steam outlet.

5-. sIn a closed circult steam generator having a portion thereof of large capacity relative to its exterior surface and a port-ion of small capacity relative to its exterior surface, means for heatlng the exter or surface of said portion of small capacity, water forcing means between said .two portions of small capacity relative to its exterior-surface,

meansv for heating the exterior surface of said portion of small capacity, water forcing means between said two portions of the generatorat one end of the portion of small capacity, and actuating. means between said two portions at the other end of the portion of small capacity operated by the differential pressure between the two portions, all moving parts being so enclosed that no part thereof is under a pressure less than that in said portion of large capacity.

7. In a closed circuit steam generator having a portion thereof of large capacity relative to its exterior surface and a portion of small capacity relative to its exterior sur-' face, means for heating one of said portions, water forcing means between said two portions atone end of the portion of small of a pressure chamber and a coil connected "at both ends with the pressure chamber,

means for heating-the coil to cause therein a pressure higherv than that in the pressure chamber, water forcmg means arranged in the connection between one end of the coil and the pressure chamber having its inlet connected with the pressure chamber and its outlet connected with the coil, and means arranged in the connection between the other end of the coil and the pressure chamber having its inlet connected with the coil and its outlet connected with the pressure chamher and operated by the difference in pressure between thefcoil and the pressure chamber and operatively connected with the water forcing means tOyCftllSfiPOSllllVG circulating of the fluids within the generator.

-9. In a generator for generating steam. the combination of a pressure chamber, and a heating coil connected at both ends with the pressure chamber, and a unit steam pump having its steam end connected betweenthe steam end of the heating coil and the upper part of the pressure chamber and having its water end connected between'the lower part ofthe pressure chamber and the inlet end of the heating coil.

4 resumes the reservoir to .t e generating member, a.

pumping apparatus in the liquid supply conduit, and a steam motor in'th'e steam delivering conduit and actuated by the steam passing therethrough, said motor being connepted to and operating the pumping appara us.

7 11. The combination with a steam gener ating member, of a reservolr for steam and liquid, a steam delivering conduit leading from the generating member to the. reservoir, a liquid supply conduit leading from the reservoir to the generatin member, a pumping apparatus in the liquid supply conduit, a steam motor in the steam delivering conduit and actuated by the steam passing therethrough, said motor being connected to and operating the pumping apparatus, and means for preventing back flow of liquid from the steam generating member to the reservoir.

12. The combination with a steam generating member, of a common drum for steam and liquid, a steam delivering conduit leadingv from the steam glenerating member to the upper portion of t e drum, a liquid supply conduit leading from the lower portion of the drulrrto the steam generating member, a pump in the latter conduit for forcing the liquid from the drum to the steam generating memberfand a motor connected to the pump for operatin it and located in the steam delivering con uit tobe actuated by-the' steam passing therethrough.

'13. The combination with a steam generating member, of a common drum for steam and liquid, a steam delivering conduit leading from the steam generating member to the upper portion of the drum, a liquid suply conduit leading from the lower portion of the drum to the steam generating member, a pump in the latter conduit for forcing the liquid from the drum to the'steam generating member, a motor connected to the pump for operating it and located in the steam delivery conduit to be actuated by the steam passing therethrough,and means for supplying liqpid to the drum.

14. he combination with a steam generating member including'a plurality of water tubes, of a plurality of pumps supplying water respectively to said tubes, a conduit for carrying ofi the steam. generated in the tubes, and a motor in the conduit driven by the steam passing therethrough, said motor being connected to all the pumps for operating them. I 15. The combination with a steam generating member including a plurality of water tubes, having water intake ends and steam discharge ends, water feed pumps having their deliveries respectively connected to the water intake ends of the tubes, a steam receiving header with which the steam discharge ends of the tubes are connected, and a motor having an inlet for receiving the steam from the header, and operated thereby, said motor being connected to all the pumps for operating the same, the outlet from the motor constituting the steam supply outlet from the steam generating memer.

16. The combination with a steam generating member, of a liquid and steam container separate therefrom, means connecting the generating member and container for directing steam from the former to the latter and liquid from the latter to the former, means'operated by the steam for causing the liquid to flow to the generator in proportion to the steam flowing from the generator, and means for causing the steam generator to be heated to a higher degree than the container.

17. The combination with a steam generating member, of a liquid and steam container separate therefrom, means connecting the generating member and container for directing steam from the former to the latter and liquid from the latter to the former, means operated by the steam for causing the liquid to flow to the generator in proportion to the steam flowing from the generator and means for heating the generator,

"and excluding the heat from the container.

18. The combination with an enclosing member, of a steam generator therein, a liquid container outside the enclosing member, means for directing liquid from the container to the generator, means for directing steam from the generator to the container, a pump in the liquid directing means, and a motor in the steam directing means connected to the pump and causing the latter to deliver liquid to the generator in proportion to the steam flowing from the generator.

19. The combination with a steam generating member including a plurality of water tubes, of means for pumping water positively into each of said tubes, a conduit for carryingofi the steam generated in the tubes, and'a motor in the conduit driven by the fluid passing therethrough, said motor being connected to the pumping means.

-20. The combination with a steam generating member including a plurality of water tubes having water intake ends and steam discharge ends, f pumping means for pumping water positively to the intake ends of each of said tubes, a steam and water drum, a connection between the steam discharge ends of the tubes and the drum, and a motor arranged in said connections and 0perated by fluid passing therethrough, said motor being connected to the water pumping means.

21. The combination with a steam generating member comprising a plurality of water tubes, of a common drum for steam and Water, means for positively pumping Water from the steam and water drum to one end of each of the water tubes, a header connecting the other ends of the water tubes,

a conduit from said header to the steam and liquid drum and a motor in said conduit driven by the fluid passing therethrough, 1 said motor being connected to the water pumping means.

In testimony whereof I aflix my signature.

SILAS F. CRABB. 

